
































































































































































































COPYRIGHT DEPOSIT. 







































HELPFUL HINTS 


ON 

Modern Locomotive 
Brakes 


Being a short treatise on E- T and 
L- T types of brakes 

Setting forth the defects , tests for 
defects , and remedies for same 


BY 

T. F. I^YONS 
546 East 109th Street 
CLEVELAND, OHIO 





Copyright, 1916 

BY 

T. F. Lyons 



JAN 13 1916 

©CIA419 57 0 

I- 





PREFACE 

In offering this little book to those 
who have to do with the operation and 
care of the locomotive brake, it is not 
.the intention to give an extended treatise 
-^on these two types of brakes, but rather 
offer such information as may be made 
use of in refreshing our memory on 
things that we already knew, but may 
have forgotten, and at the same time 
point out the different defects of the ap¬ 
paratus, with tests for locating the de¬ 
fects, and possible remedies for same. 
While much more might be said in regard 
to making repairs while on the road, yet 
the writer has well in mind the fact that 
locomotives are not as well supplied with 
tools and repair parts as they might be. 
While again, in these busy days, about 
all that is asked of the engineer is to 
*be able to make a quick repair, if pos¬ 
sible, and not cause delay to train move¬ 
ment; keeping well in mind that Safety 
First should be the motto of every man 
in train service. 

That benefit might be derived from 
what is here written, it is suggested that, 
where possible, the different tests and 
remedies here given be tried out before 
it becomes necessary to use them, as it 
will be found that an ounce of experience 
is worth a pound of book knowledge. 


INDEX 


Page 

Westinghouse No. 6 E-T Equipment.... 5 

Pump Governor Tests.... . 8 

Broken Pipes . 10 

Air Pumps . 11 

Caring for the Pump . 15 

Defects of the Pump . . 16 

Locating Defects and Remedy for 

Same . 18 

Air Cylinder Lubricator . 22 

Automatic Brake Valve . 23 

Brake Valve Defects and Remedy 

for Same . 26 

Peed Valve .1. 31 

Independent Brake Valve . 34 

Dead Engine Feature .. 37 

Distributing Valve' . 39 

Safety Valve . 45 

Quick-Action Cap . 46 

Broken Pipes .. 47 

Distributing Valve Defects . 53 

Locomotive Brake Creeps On . 56 




















INDEX— Continued 


Page 

New York L-T Equipment .... 57 

Duplex Pump Governor ... 60 

Duplex Air Pumps —. . 61 

Steam End of Pump ___ 61 

Air End of Pump ... 62 

Defects of the Pump . 64 

Type L Automatic Brake Valve . 69 

Double Pressure Feed Valve . 69 

Independent Brake Valve . . 69 

Automatic Control Valve . 71 

Safety Valve . 78 

Quick-Action Cap .— 79 

Dead Engine Feature . 80 

Broken Pipes . 80 

Control Valve Defects . 86 

Locomotive Brake Creeps On . 88 





















WESTINGHOUSE No. 6 E-T 
EQUIPMENT 

Q. — On what is this brake designed to 
operate ? 

A. — On engine and tender. 

Q. — What are some of the many advan¬ 
tages of the E-T equipment over older 
types of locomotive brakes? 

A. — May be used on engines in any 
class of service. Brake cylinder pressure 
not affected by piston travel or brake 
cylinder leakage. Locomotive brake may 
be applied or released independent of the 
train brake. Brake on second engine of 
a doubleheader may be applied or re¬ 
leased independent of the brakes on the 
leading engine or train. 

Q. — Name the parts of the equipment 
and explain in a general way their duties. 

A. — 1. The air pump, to compress the 
air used on the locomotive and cars. 

2. The duplex governor, to control the 
pump when the desired pressure is ob¬ 
tained in the main reservoir. 

3. The main reservoir, in which to store 
a large volume of air for the prompt 
charging and recharging of the brakes 
and to collect the moisture and dirt in the 
air. 

4. The main reservoir cut-out cock, 
which, when closed, cuts off the com¬ 
munication between the main reservoir 
and brake system. 


6 


Helpful Hints on 


5. The automatic brake valve, to oper¬ 
ate the locomotive and train brakes. 

6. The equalizing reservoir, to furnish 
the proper volume of air above the equal¬ 
izing piston. 

7. The independent brake valve, to 
operate the locomotive brake independent 
of the train brake. 

8. The feed valve, to regulate the brake 
pipe pressure, when the automatic brake 
valve is in running or holding position. 

9. The reducing valve, to regulate the 
pressure in the independent brake valve 
and signal line. 

10. The distributing valve, its reservoir 
and safety valve, to admit air to and 
from the brake cylinders on the locomo¬ 
tive, in applying and releasing the brakes, 
and to control the brake cylinder pressure 
within the prescribed limits. 

11. Two duplex air gauges, one to in¬ 
dicate the main reservoir and equalizing 
reservoir pressures, the other to indicate 
the brake pipe and locomotive brake 
cylinder pressures. 

12. The dead engine feature, by which 
air may be supplied to the main reservoir 
of an engine, the pump of which is in¬ 
operative. The above, with the neces¬ 
sary brake cylinders, air strainers, cut-out 
cocks, hose couplings and piping, go to 
make up the No. 6 E-T equipment. 

Q.—Commencing at the air pump, name 
the different pipes and their connections. 


Modern Locomotive Brakes 7 

A.—Discharge pipe: To connect the 
air pump to the first main reservoir. 

Connecting pipe: To connect the two 
main reservoirs. 

Main reservoir pipe: To connect the 
second main reservoir to the maximum 
head of the pump governor, distributing 
valve, feed valve, reducing valve and 
automatic brake valve. This pipe also 
furnishes air to the connections of all 
other air-operated appliances on the loco¬ 
motive. 

Feed valve pipe: To connect the feed 
valve to the automatic brake valve. 

Excess pressure pipe: To connect the 
feed valve pipe to the chamber above the 
diaphragm of the excess pressure head of 
the governor. 

Excess pressure operating pipe: To 
connect the automatic brake valve to the 
chamber below the diaphragm of the ex¬ 
cess pressure head of the governor. 

Reducing valve pipe: To connect the 
reducing valve to the air signal line and 
independent brake valve. 

Brake pipe: To connect the automatic 
brake valve with the distributing valve 
and train brakes. 

Brake cylinder pipe: To connect the 
distributing valve to the different brake 
cylinders on the locomotive. 

Application cylinder pipe: To connect 
the application cylinder of the distribut- 


8 


Helpful Hints on 


mg valve to the independent and auto¬ 
matic brake valves. 

Distributing valve release pipe: To 
connect the application cylinder exhaust 
port with the automatic brake valve, 
through the independent brake valve, 
when the latter is in running position. 


Pump Governor Tests 

Q.—What is the first thing to be ob¬ 
served when testing the governor? 

A.—That all pipes are open and free 
from dirt, all connections tight, and that 
the vent port and drain port are open. 

Q.—In what position should the auto¬ 
matic brake valve be placed when adjust¬ 
ing the excess pressure head; the max¬ 
imum pressure head? 

A.—Running position for the excess 
pressure head; lap position for the max¬ 
imum pressure head. 

Q.—If with the automatic brake valve 
in running position the brake pipe and 
main reservoir pressures do not stand 
twenty pounds apart, where would you 
look for the trouble? 

A.—Would first learn if the maximum 
pressure head was properly adjusted, and 
if it was, would look for the trouble in 
the adjustment of the regulating spring 
in the excess pressure head. 

Q.—What should be done? 

A.—The regulating spring in the ex- 


Modern Locomotive Brakes 


9 


cess pressure head should be properly- 
adjusted. 

Q.—How should the adjustment of the 
regulating spring in either pressure head 
be made? 

A.—By- removing the cap nut and 
screwing the regulating nut up or down 
as may be required. 

Q.—What would be the effect if one 
or both pin valves leaked? 

A.—Would cause a delay in the open¬ 
ing of the steam valve after the pin valve 
had seated; and if the air leaked by 
faster than it could escape through the 
relief port, pressure would accumulate in 
the chamber above the governor piston, 
forcing it downward, so as to wholly or 
partly close the steam valve.' 

Q.—How can you tell if the pin valve 
leaks ? 

A.—If the pin valve leaks, it will be 
indicated by a constant blow of air at the 
relief port. 

Q—What would be the effect of the 
vent port stopping up? 

A.—The duty of the vent port is to 
allow the air to escape from the chamber 
above the governor piston when the pin 
valve closes so that the pump will start 
promptly. If the port be stopped up, the 
air will have to leak past the packing ring 
of the governor piston, and out the drip 
port; how quickly it will do this depends 
on the fit of the packing ring; if the fit 


10 


Helpful Hints on 


is at all close, the steam valve may not 
open until some time after the pin valve 
closes. 

Q.—What does steam blowing at the 
drain pipe indicate? 

A.—A worn steam valve stem or bush. 

Q.—What would be the effect of a 
frozen or stopped up drain pipe? 

A.—If the drain pipe is frozen or 
stopped up, and the stem of the steam 
valve leaking, steam will feed up into the 
chamber under the governor piston and 
prevent the piston being forced down¬ 
ward to close the steam valve; the pump 
will therefore continue to work until the 
main reservoir pressure is about equal to 
boiler pressure. 

Broken Pipes 

Q.—What would be the effect if the 
upper pipe to the excess pressure head 
broke off? 

A.—The pump would stop when the 
main reservoir pressure was in excess of 
40 pounds. 

Q.—If this pipe breaks, what should 
be done? 

A.—Plug the pipe toward the feed 
valve pipe and put a blind gasket in the 
pipe leading to the chamber below the 
diaphragm of the excess pressure head. 

Q.—What should be done if the pipe 
leading to the chamber below the dia¬ 
phragm breaks? 


Modern Locomotive Brakes 11 


A.—Plug the pipe toward the brake 
valve and proceed. 

Q.—With one or both of the pipes 
leading to the excess pressure head 
broken, what would control the pump? 

A.—The maximum pressure head. 

Q.—What should be done if the pipe 
leading to the maximum pressure head 
breaks ? 

A.—Plug the pipe toward the main 
reservoir and proceed. 

Q.—With this pipe broken what would 
control the pump? 

A.—The excess pressure head would 
control the pump in release, running or 
holding position; but would have no con¬ 
trol in lap, service or emergency position, 
or when the main reservoir cut-out cock 
was closed; therefore, the action of the 
pump would have to be governed by 
throttling the steam valve. 

Air Pumps 

Q.—How many different size pumps, in 
general use on railroads, are made by the 
Westinghouse Air Brake Co.? 

A.—Three. They are known as the 
9% -inch, 11-inch, and cross-compound 
pumps. 

Q.—What is meant by the figures 9% 
and 11? 

A.—These figures indicate the diameter 
of the steam and air cylinders of these 
pumps. 


12 


Helpful Hints on 


' Q.—What is the length of stroke? 

A.—The 9 y 2 -inch pump has a 10-inch 
stroke, while the 11-inch has 12-inch 
stroke. 

Q.:—Is there any difference in the oper¬ 
ation of the 9%-inch and the 11-inch 
pumps? 

A.—-No; the arrangement of the valve 
gear and air valves are the same in both 
pumps; the only difference in these two 
pumps being in their capacity. 

Q.—What is meant by a cross-com¬ 
pound pump? 

A.—This means that both the steam 
and air are compounded; that is, the 
steam is used the second time before it is 
exhausted, while the air is compressed the 
second time before it is forced into the 
main reservoir. 

Q.—Is the valve gear of the cross-com¬ 
pound pump similar to that of the 9 14 - 
inch and 11-inch pumps? 

A.—Yes. 

Q.—Is a slide valve used to distribute 
the steam the same as in the 9%- and 
11-inch pumps? 

A.—No; a piston type of valve is used, 
consisting of three piston heads, which 
control the flow of steam to and from 
both cylinders. 

Q.—How many cylinders has the cross¬ 
compound pump? 

A.—Four: two steam cylinders and 
two air cylinders. 


Modern Locomotive Brakes 13 


Q.—Name the different cylinders. 

A.—High and low pressure steam cylin¬ 
ders; high and low pressure air cylinders. 

Q.—What is the diameter of the dif¬ 
ferent cylinders'? 

A.—The high pressure steam cylinder 
is 8% inches; low pressure steam cylin¬ 
der, 14^ inches; low pressure air cylin¬ 
der, 14 y 2 inches; high pressure air cylin¬ 
der, 9 inches. 

. Q.—What is the length of stroke? 

A.—Twelve inches. 

Q.—How are the cylinders located? 

A.—The low pressure air cylinder is 
under the high pressure steam cylinder, 
and the high pressure air cylinder is 
under the low pressure steam cylinder. 

Q.—Is the low pressure steam piston 
in any way connected with the valve gear 
of the pump? 

A.—No; this is simply a floating pis¬ 
ton and depends entirely on the exhaust 
steam from the high pressure steam 
cylinder for its steam supply. 

Q.—How many air valves used in the 
9 Y 2 - and 11-inch pumps? 

A.—Four: two receiving and two dis¬ 
charge valves. 

Q.—How many air valves used in the 
cross-compound pump? 

A.—Ten: four receiving, four inter¬ 
mediate discharge and two final discharge 
valves. 


14 


Helpful Hints on 


Q.—Are the air valves in the different 
pumps the same size? 

A.—No; the valves used in the fl¬ 
inch pump are all the same size and are 
IV 2 inches in diameter; those used in the 
11-inch pump are all one size and aie 2 
inches in diameter; while in the cross¬ 
compound pump the receiving and final 
discharge valves are one size, and of the 
size used in the 11-inch pump, and the 
intermediate discharge valves are all one 
size, and of the size used in the 9%-inch 
pump. 

Q.—What should be the lift of the air 
valves? 

A.—The air valves in all Westinghouse 
pumps should have the same lift; namely, 
h 3 2 of an inch. 

Q.—If the air valves have too much 
lift, what will be the result ? 

A.—Will cause the pump to pound. 

Q.—What are the duties of the air 
valves? 

A.—The receiving valves admit the air 
to the pump from and prevent its return 
to the atmosphere; the discharge valves 
allow the air to pass from the pump to 
the main reservoir and prevent its return; 
while the intermediate discharge valves, 
in the cross-compound pump, permit the 
air to pass from the low pressure f r 
cylinder to the high pressure air cylinder, 
and prevent its return to the low pressure 
air cylinder. 


Modern Locomotive Brakes 15 

Q. — What kind of oil should be used in 
the steam and air cylinders and on the 
swab ? 

A. — Yalve oil. 

Q. — Why not use engine oil? 

A. — Engine oil might be used were it 
not that its burning point is below the 
working temperature of the cylinders of 
the pump. 

Caring for the Pump 

Q.—How should an air pump be 
started? 

A. — The pump should be started slow, 
with the drain cocks open, to allow the 
water of condensation to escape; and as 
no provision is made in the steam end to 
cushion the piston at the end of its stroke, 
it should be allowed to work slowly until 
a pressure of thirty or forty pounds is 
accumulated in the main reservoir; the 
piston having to work against this pres¬ 
sure, will be cushioned at the end of each 
stroke. After the pump is warm, the 
drain cocks should be closed and the 
throttle opened sufficient to run the pump 
at the proper speed. 

Q. — At what speed should the pump be 
run to obtain the best results? 

A. — At 100 to 120 single strokes per 
minute. 

Q—ITow should the pump be lubri- 
crated? « 

A. — After the water has worked out of 


16 


Helpful Hints on 


the pump the lubricator should be started 
and allowed to feed freely until eight or 
ten drops have passed to the pump; the 
feed should then be reduced to an amount 
sufficient for proper lubrication. 

Q.- — Does the low pressure air cylinder 
of a cross-compound pump require as 
much oil as the high pressure cylinder? 

A.—No. 

Q.—Why? 

A. — The low pressure air cylinder does 
not require as much oil, as it is constantly 
receiving cool air from the atmosphere, 
and compresses it to a pressure of about 
forty pounds only; therefore, but little 
heat is created, which means but little 
oil is required; whereas the air in the 
high pressure air cylinder has to be com¬ 
pressed to a pressure equal to that car¬ 
ried in the main reservoir, and as the air 
this cylinder receives is compressed air 
from the low pressure air cylinder, the 
temperature will be much higher, there¬ 
fore will require lubricating oftener. 

Defects of the Pump 

Q. — What are some of the common 
causes for the air pump stopping? 

A. — Lack of lubrication, bent or broken 
reversing rod, loose or worn reversing 
plate, nuts on air end of piston coming 
off, defective pump governor, and in ad¬ 
dition, with the cross-compound pump, 
final discharge valve broken, or stuck 


Modern Locomotive Brakes 17 


open, or packing rings in the main valve 
pistons breaking and catching in the 
steam ports. 

Q.—What causes the piston to make an 
uneven stroke ? 

A.—This may be caused by broken or 
stuck open air valves, or valves not having 
the proper lift. Where the piston short- 
strokes, it is generally caused by over¬ 
lubrication of the steam end. 

Q.—What are some of the common 
causes for the pump running hot? 

A.—The overheating of a pump may 
be due to one of the following causes: 
running at high speed; working against 
high pressure; packing rings in air pis¬ 
ton badly worn; air cylinder worn; de¬ 
fective air valves; air passages in pump 
or air discharge pipe partially stopped 
up; leaky piston rod packing. 

Q.—What will cause the air pump to 
run slow? 

A.—This may be caused by leaky pack¬ 
ing rings in the air piston; final dis¬ 
charge valves leaking, or air passages 
partially stopped up. A defective pump 
governor may also cause the pump to run 
slow. 

Q.—What will cause the pump to run 
very fast and heat, and not compress any 
air ? 

A.—This may be caused by the strainer 
becomifig clogged with ice or dirt, pre¬ 
venting air entering the cylinder. 


18 


Helpful Hints on 


Locating Defects and Remedy 
for Same 

Q. — If, when steam is first turned on, 
the piston makes a stroke up and stops, 
where would you look for the trouble? 

A. — The shoulder on the reversing rod 
may be worn; the opening in the revers¬ 
ing plate too large to engage the shoulder 
on the reversing rod; loose reversing 
plate studs preventing the piston travel¬ 
ing far enough to reverse the pump, or 
the ma*n valve stuck in its position at the 
right. 

Q. — If a piston makes a stroke up and 
a stroke down and stops, where is the 
trouble? 

A. — This may be caused by a loose re¬ 
versing plate, or the button on the lower 
end of the reversing rod worn or broken 
off, or the nuts off the piston rod in the 
air end of the pump, or the main valve 
stuck in its position at the left. 

Q. — If a receiving valve breaks or 
sticks open, how may it be located? 

A. — The air will flow back to the at¬ 
mosphere as the piston moves toward the 
defective valve and may be detected by 
holding the hand over the strainer. 

Q. — If a receiving valve in the cross¬ 
compound pump breaks, what may be 
done? 

A. — Remove the broken valve, blocking 
the opening made by its removal, and as 


Modern Locomotive Brakes 19 

there are two upper and two lower receiv¬ 
ing valves the pump will now take air 
through the other valve. 

Q.—If an intermediate discharge valve 
breaks or sticks open, how may it be 
located? 

A.—No air will be taken into the 
pump, as the piston moves from defective 
valve and may be located by holding the 
hand over the strainer. 

Q.—If an intermediate discharge valve 
breaks, what may be done? 

A.—Remove the broken valve, blocking 
the opening made by its removal, and as 
there are two upper and two lower inter¬ 
mediate discharge valves the air will now 
pass from the low pressure cylinder to 
the high pressure cylinder through the 
other valve. 

Q.—If a final discharge valve breaks, 
what effect will it have on the pump? 

A.—Will cause the pump to stop when 
the main reservoir pressure is in excess 
of forty pounds. 

Q.—IIow would you test for a defective 
final discharge valve? 

A.—To test for this defect, bleed 
the main reservoir pressure below forty 
pounds, and if the pump starts it indi¬ 
cates a defective discharge valve. 

Q—If a final discharge valve breaks, 
what may be done? 

A.—As the receiving valves and final 
discharge valves are the same size, the 


20 


Helpful Hints on 


broken final discharge valve may be re¬ 
placed by one of the receiving valves 
blocking the opening made by the removal 
of the receiving valve. 

Q.—What will cause the piston to make 
a quick up stroke? 

A. — This may be caused by a broken or 
stuck-open upper receiving or lower dis¬ 
charge valve. 

Q. — How will this cause the piston to 
make a quick up stroke? 

A. — In the case of an upper receiving 
valve, air would be drawn into the cylin¬ 
der on the down stroke, but would blow 
back to the atmosphere on the up stroke; 
therefore the piston, having no work to 
do, will move up quickly. If the lower 
discharge valve were at fault, main reser¬ 
voir air would flow back under the piston, 
causing a quick up stroke, as the main 
reservoir pressure would assist the steam 
pressure in the movement of the piston; 
the down stroke, however, would be slow, 
as the piston would have to work against 
main reservoir pressure from the begin¬ 
ning of the stroke. No air would be 
taken into the pump on the up stroke. 

Q. — What will cause the piston to make 
a quick down stroke? 

A. — Lower receiving or upper discharge 
valve broken or stuck open. 

Q. — Where piston rod packing is blow¬ 
ing bad, what may be done to stop it? 

A. — Piston rod packing blowing gen- 


Modern Locomotive Brakes 21 


erally indicates lack of proper lubrica¬ 
tion, and by cleaning and oiling the swab 
the trouble may be overcome. However, 
there are times when leakage by the pack¬ 
ing is so great that the oil is blown off 
the swab as fast as it is applied, there¬ 
fore is of no value in lubricating the 
parts. Where this condition exists, a 
little hard grease wrapped up in an old 
flag and tied around the piston rod will 
insure its being lubricated. 

Q.—How often should the air end of 
the pump be oiled? 

A.—No fixed rule can be given, as so 
much depends on the condition of the 
pump, as well as the amount of work re¬ 
quired; but in any case it should be used 
sparingly. 

Q.—Should oil be introduced through 
the strainer? 

A.—No; as oiling in this manner has a 
tendency to gum up the air passage and 
air valves. 

Q.—If the pump stops, how can you 
tell if the pump governor is responsible 
for the trouble? 

A.—By opening the drain cock in the 
steam passage between the governor and 
the pump; if steam flows freely, the 
trouble is in the pump; if not, it is in the 
governor. 

Q.—How may a pump often be started 
when it stops? 

A.—By closing the steam throttle for 


22 Helpful Hints on 

a few seconds, then opening it quickly; 
if this does not start it, try tapping the 
main valve chamber. This will usually 
overcome the trouble where the pump 
stops on account of lack of lubrication. 

Q.—What will cause a pump to short- 
stroke or dance? 

A.—Too much oil in the steam end; 
bent reversing rod; or low steam pres¬ 
sure, as when the governor has almost 
shut off the steam. 

Air Cylinder Lubricator 

Q.—What is the purpose of the air 
cylinder lubricator ? 

A.—To furnish a practical and an ef¬ 
fective means of securing proper lubrica¬ 
tion for the air cylinder of the pump. 

Q.—Of what does this cylinder lubri¬ 
cator consist? 

A.—Of three parts: sight-feed fitting, 
emergency throttle valve, and the check 
valve connection. 

Q.—What are the duties of the several 
parts? 

A.—The sight-feed attachment is to 
regulate the amount of oil to the pump. 
The emergency throttle valve is used to- 
throttle the pressure from the lubricator 
to the sight-feed valve, and to cut off the 
oil completely when not in use. The 
cheek valve connection is connected 
directly to the air cylinder of the pump, 
and consists of a ball check seating up- 


Modern Locomotive Brakes 23 


ward, which prevents the compressed air 
from entering the oil pipe. 

Q.—To what is the air cylinder lubri¬ 
cator connected? 

A.—To the oil reservoir of the main 
lubricator, at one end, and the air cylin¬ 
der of the pump at the other. 

Q.—Explain the operation of the lubri¬ 
cator. 

A.—First, the emergency throttle 
should be opened about one-half turn and 
then closed; then the sight-feed valve 
opened a sufficient length of time to per¬ 
mit from five to eight drops of oil to pass 
to the pump, then closed. This lubricator 
must not be treated as a lubricator for 
continuous feeding, but must be employed 
rather as a valve for use only when it 
becomes necessary to feed a few drops of 
oil to the pump. 

Automatic Brake Valve 

Q.—Name the different positions of the 
II-6 brake valve. . 

A.—Release, running, holding, lap, 
service, and emergency. 

Q.—With what type of locomotive 
brake is this valve used? 

A.—With the E-T equipment, of which 
it is a part. 

Q.—To what is the automatic brake 
valve attached? 

A.—To the brake valve pipe bracket. 


24 


Helpful Hints on 


Q. — Are there any pipe connections 
direct to the brake valve? 

A. — No; all pipe connections are made 
direct to the pipe bracket; this allows for 
the changing of the brake valve without 
the breaking of the pipe joints. 

Q.—What is the purpose of release 
position ? 

A. — To provide a large and direct 
opening from the main reservoir to the 
brake pipe, for the free flow of air, when 
charging and recharging the brakes. 

Q. — What pressure will be had in the 
brake pipe if the brake valve be left in 
release position? 

A. — Main reservoir pressure. 

Q. — Can the' locomotive brake be re¬ 
leased by the automatic brake valve in 
release position? 

A. — No ; as the port in the automatic 
brake valve to which the distributing 
valve release pipe is attached is blanked 
in this position of the valve. 

Q. — What is the purpose of running 
position, and when should it be used? 

A. — This is the proper position for the 
brake valve when the brakes are charged 
and not in use, also when it is desired to 
release the locomotive brake with this 
valve. This position of the valve may be 
used in releasing the brakes on short 
trains of, say, six or eight cars. In this 
position the brake pipe pressure is main¬ 
tained at a predetermined amount by the 


Modern Locomotive Brakes 25 


feed valve, as all air that now enters the 
brake pipe and equalizing reservoir must 
pass through the feed valve. 

Q.—What is the purpose of holding 
position ? 

A.—To hold the locomotive brake ap¬ 
plied while recharging the brakes. The 
charging of the brake pipe and equalizing 
reservoir is the same in holding as in run¬ 
ning position; in other words, the only 
difference between the two positions is 
that the locomotive brake is released in 
running position, while it is held applied 
in holding position. 

Q.—What is the purpose of lap posi¬ 
tion? 

A.—To hold both the locomotive and 
train brakes applied after an automatic 
application. In this position all ports in 
the brake valve are closed. 

Q.—What is the purpose of service 
position? 

A.—This position of the brake valve 
enables the engineer to make a gradual 
reduction of brake pipe pressure, thus 
causing a service application of the 
brakes. 

Q.—What is the purpose of emergency 
position? 

A.—In this position of the brake valve, 
the brake pipe is connected directly with 
the atmosphere through the large ports 
in the valve, causing a sudden reduction 
of brake pipe pressure, this in turn caus- 


26 


Helpful Hints on 


ing the distributing valve on the engine 
and all operating triple valves on cars in 
the train to move to emergency position, 
thus insuring a quick and full application 
of the brake. 

Q.—How should the brake valve be 
handled when making an emergency ap¬ 
plication of the brake? 

A.—The valve should be placed in full 
emergency position and left there until 
the train stops, even though the danger 
may have disappeared. 

Brake Valve Defects and 
Remedy for Same 

Q.—If the handle of the brake valve 
does not operate easily, what may be the 
trouble and how remedied? 

A.—If the brake valve does not operate 
freely, it is probably due to a dry rotary 
valve or rotary valve key gasket. This 
trouble may be remedied by first closing 
the cut-out cock under the brake valve, 
then closing the main reservoir cut-out 
cock, and when the air pressure has 
escaped, remove the oil plug in the valve 
body and fill the oil hole with oil, then 
move the valve from release to emergency 
position and back a few times; this gives 
the oil a chance to work under the rotary; 
then refill the oil hole and replace the 
plug; next, remove the cap nut from the 
rotary valve key, fill the oil hole, and 
push doAvn on the key; this allows the 


Modern Locomotive Brakes 27 

oil to get down on the key gasket; again 
fill the oil hole and replace the cap nut. 

Q.—What will cause the handle to move 
hard over notches of the different posi¬ 
tions of the valve? 

A.—This is caused by the handle bolt 
or latch becoming dry; a few drops of 
oil on the parts will overcome the trouble. 

Q.—What will cause a constant blow 
at the brake pipe exhaust port, and what 
may be done to overcome it? 

A.—This indicates that the brake pipe 
exhaust valve is being held off its seat, 
due no doubt to dirt.; tapping the side 
of the valve will sometimes stop the blow; 
if not, close the brake pipe cut-out cock 
and make a heavy service reduction; next, 
place the handle in release position; this 
will cause a strong blow at the exhaust 
port, which will invariably remove the 
trouble. 

Q.—If the pipe connecting the brake 
valve with the equalizing reservoir breaks, 
can the brake be operated with the auto¬ 
matic brake valve? 

A.—Yes. 

Q.—IIow can this be done? 

A.—By placing a bliud gasket in the 
pipe connection at the brake valve and 
plugging the brake pipe exhaust port. 
To apply the brake, move the handle care¬ 
fully toward emergency position, making 
the reduction gradually through the 
direct exhaust port; when the desired re- 


28 


Helpful Hints on 


duction is made, the valve should be 
moved gradually back to lap position. 

Q.—What would be the effect if the 
valve were moved to lap quickly? 

A. — Would cause the release of the 
brakes on the head end of the train. 

Q. — What will cause air to blow at the 
brake pipe exhaust port when the valve 
is moved to lap position? 

A. — This is caused by a leak from the 
equalizing reservoir or its connections, 
which reduces the pressure in chamber D 
above the equalizing piston, allowing 
brake pipe pressure under the piston to 
force it up, unseating the brake pipe 
exhaust valve, permitting the air to flow 
to the atmosphere. 

Q. — What is the time required to re¬ 
duce the equalizing reservoir pressure 
twenty pounds? 

A. — From six to seven seconds, with a 
70-pound pressure, and five to six seconds 
with a 110-pound pressure. 

Q. — If the time required is greater 
than that here given, what does it indi¬ 
cate? 

A. — This indicates leakage of air into 
chamber D from either the main reser¬ 
voir port, feed valve port, or brake pipe 
port. 

Q.- — If, when the automatic brake valve 
is moved to service position, and air ex¬ 
hausts at the back of the brake valve, and 
the brake pipe exhaust port does not 


Modern Locomotive Brakes 29 

open, neither does the black hand on the 
gauge drop back, what might be the 
trouble ? 

A. — This indicates leakage of air into 
chamber D faster than it can be ex¬ 
hausted through the preliminary exhaust 
port, therefore the pressure above the 
equalizing piston will not be reduced, 
consequently the piston will not rise to 
unseat the brake pipe exhaust valve. 
Leakage into this chamber may some¬ 
times be overcome by tightening the bolts 
in the brake valve. 

Q. — Can the brakes be applied in serv¬ 
ice where this condition exists? 

A. — Yes; by moving the handle care¬ 
fully toward emergency position, making 
a gradual reduction of brake pipe pres¬ 
sure, service braking may be done the 
same as where an equalizing reservoir 
pipe is broken off. 

Q. — -What defect in the brake valve 
will cause the brake pipe and main reser¬ 
voir pressure to equalize when the handle 
is in running position? 

A. — This may be caused by leakage 
past the rotary valve or the body gasket. 

Q. — How may it be known which part 
is at fault? 

A. — To determine which part is at 
fault, close the cut-out cock under the 
brake valve and move the handle to serv¬ 
ice position, exhausting all air from 
chamber D and the brake pipe; then re- 


30 


Helpful Hints on 


turn the handle to lap position. Leakage 
of air past the rotary valve is generally 
into the brake pipe port, which allows the 
air to come in under the equalizing pis¬ 
ton, forcing it upward, unseating the 
brake pipe exhaust ’valve, allowing this 
air to escape to the atmosphere at the 
brake pipe exhaust port. Leakage past 
the body gasket allows air to enter cham¬ 
ber D, above the equalizing piston, hold¬ 
ing it in its lower position, keeping the 
brake pipe exhaust valve closed, thereby 
preventing the escape of this air to the- 
atmosphere. Since the capacity of the 
equalizing reservoir and chamber I) is 
small, such a leak will cause the black 
hand to quickly move up to the position 
of the red hand. 

Q. — What effect will the absence of the 
brake pipe exhaust fitting have in service 
braking? 

A. — This may cause an undesired 
emergency application of the brake, espe¬ 
cially with a short train. 

Q.—If, while making a service applica¬ 
tion of the brake, the brake pipe exhaust 
valve closes suddenly, and the black hand 
drops quickly, what, may be the cause? 

A.—The sudden closing of the brake 
pipe exhaust valve means that for some 
reason there has been a sudden drop of 
brake pipe pressure; and this may be 
caused by a burst hose, train parting, or 
the triple valves throughout the train .go- 


Modern Locomotive Brakes 31 • 

ing to emergency position. If the black 
hand goes back to the pin, it indicates a 
burst hose or train parted; whereas, if 
air again begins to blow at the exhaust 
port, it indicates a defective triple valve 
some place in the train, or a defective 
distributing valve on the engine. 

Feed Valve 

Q. — What is the duty of the feed 
valve ? 

A. — To control and maintain a constant 
pressure in the brake pipe when the 
brake valve is in running or holding posi¬ 
tion. 

Q.—Name the pipe connections to the 
feed valve. 

A. — Main reservoir pipe, which brings 
main reservoir air to the feed valve; feed 
valve pipe, which conducts main reservoir 
air, at a reduced pressure, to the feed 
valve port in the automatic brake valve. 

Q. — With the automatic brake valve in 
running or holding position, and the regu¬ 
lating spring properly adjusted, what de¬ 
fect in the feed valve will cause the brake 
pipe pressure to equalize with that in the 
main reservoir? 

A.—This may be caused by a defective 
feed valve case gasket, permitting main 
reservoir air to leak into the feed valve 
pipe, or leakage past the supply valve, or 
the regulating valve held from its seat, or 


32 


Helpful Hints on 


the supply valve piston too tight a fit in 
its cylinder. 

Q.—With the engine alone, the brake 
pipe pressure will equalize with that in 
the main reservoir, while when coupled to 
a train the pressure will remain at that 
for which the feed valve is adjusted; 
where is the trouble? 

A.—This is caused by light leakage of 
main reservoir air into the brake pipe, 
and may be coming past the rotary valve, 
body gasket or feed valve, and with the 
lone engine is sufficient to raise the brake 
pipe pressure to that in the main reser¬ 
voir; while when coupled to a train, the 
brake pipe leakage of which is greater 
than that of the feed valve, this will not 
be noticed. 

Q.—How should the feed valve be 
tested ? 

A.—With the brakes released, and 
charged to the adjustment of the feed 
valve, create a brake pipe leak of from 
seven to ten pounds and note the black 
hand on the brake pipe gauge. The fluc¬ 
tuation of this hand will indicate the 
opening and closing of the feed valve, 
which should not permit a variation of 
over two pounds in the brake pipe pres¬ 
sure; if it does, it indicates a dirty con¬ 
dition of the valve, and should be cleaned. 

Q.—If the brake pipe charges too 
slowly when nearing the maximum pres¬ 
sure, where is the trouble? 


Modern Locomotive Brakes 33 


A—This may be caused by a loose- 
fitting supply valve piston, or the port 
past the regulating valve partly stopped 

up. 

Q.—If the main reservoir pipe connec¬ 
tion to the feed valve breaks, what should 
be done? 

A.—This will cause a loss of main 
reservoir air, and pipe must be plugged 
toward the main reservoir. 

Q.—With this pipe broken, how can the 
brake pipe be charged, and where should 
the brake valve handle be carried ? 

A.—As no air now comes to the feed 
valve to charge the train in running or 
holding position, the handle must be car¬ 
ried in full release position. 

Q.—What must be done if the pipe be¬ 
tween the feed valve and the automatic 
brake valve breaks? 

A.—Slack off on the .regulating nut of 
the feed valve until all tension is removed 
from the regulating spring and plug the 
pipe toward the brake valve—this to stop 
the flow of air. The brake valve will 
have to be handled the same as with a 
broken main reservoir connection. 

Q.—If the brake valve be carried in 
release position, will there not be a tend¬ 
ency for the locomotive brake to creep 
on? 

A.—Yes. 

Q.—How can this be avoided? 

A.—This trouble may be overcome by 


34 


Helpful Hints on 


disconnecting the release pipe at the dis¬ 
tributing valve. 

Q.—With either or both of these pipes 
broken, and the brake valve handle car¬ 
ried in release position, what will control 
the main reservoir and brake pipe pres¬ 
sure? 

A.—The maximum pressure head of the 
pump governor, which should be adjusted 
to the brake pipe pressure carried. 

Q.—If the feed valve becomes defective 
so that it will not control brake pipe 
pressure, what may be done? 

A.—As the reducing valve used for the 
straight air and the feed valve are prac¬ 
tically the same, they may be changed one 
for the other, the reducing valve taking 
the place of the feed valve. 

Independent Brake Valve 

Q.—To what is the independent brake 
valve attached? 

A.—To a pipe bracket. 

Q.—Are there any pipe connections 
direct to this valve? 

A.—No; all pipe connections are made 
direct to the pipe bracket as with the 
automatic valve. 

Q.—Name the pipes and their connec¬ 
tions to the independent brake valve. 

A.—Reducing valve pipe, which leads 
to the reducing valve. Application cylin¬ 
der pipe, which leads to and is the middle 
pipe on the left side of the distributing 


Modern Locomotive Brakes 35 


valve; also connects to the automatic 
brake valve. Distributing valve release 
pipe, which leads to and is the lower pipe 
on the left side of the distributing valve; 
this pipe also has ,a connection between 
the independent and automatic brake 
valves. 

Q.—Name the position of the brake 
valve. 

A.—Release, running, lap, slow-applica- 
tion position, quick-application position. 

Q.—What is the purpose of release 
position ? 

A.—To release the locomotive brake 
when the automatic brake valve is in 
other than running position. 

Q.—What is the purpose of running 
position? 

A.—Running position is the proper 
position for the brake valve when not in 
use, and to release the locomotive brake 
when the automatic brake valve is in run¬ 
ning position. 

Q.—What is the purpose of lap posi¬ 
tion? 

A.—To hold the locomotive brake ap¬ 
plied after an independent application. 

Q.—What is the purpose of slow-ap- 
plication position? 

A.—This position may be used when it 
is desired to make a light or gradual 
application of the brake, as in stretching 
or bunching the slack of a train. 


36 


Helpful Hints on 


Q. — What is the purpose of quick-ap¬ 
plication position? 

A. — To apply the locomotive brake 
quickly, as in short switching. 

Q.—What is the- purpose of the return 
spring? 

A. — To automatically return the valve 
to running position from full release posi¬ 
tion; also from quick- to slow-application 
position. 

Q. — Why is this done? 

A. — The automatic return from release 
to running position is to prevent leaving 
the valve in release position, as in this 
position the automatic brake would not 
remain applied on the locomotive. The 
action of the spring in the return of the 
valve from quick to slow application is 
simply to make more marked the latter 
position; that is, to act as a stop for this 
position. 

Q. — What pressure is usually developed 
with this brake? 

A. — About 45 pounds. 

Q. — What controls this pressure? 

A. — The reducing valve, which regu¬ 
lates the pressure in the reducing valve 
pipe and independent brake valve. 

Q. — If the pipe between the reducing 
valve and independent brake valve 
breaks, what must be done? 

A. — This pipe breaking will cause a 
loss of main reservoir air, which may be 


Modern Locomotive Brakes 37 


stopped by backing off on the regulating 
nut in the reducing valve. 

Q.—If this pipe breaks, can the loco¬ 
motive brake be applied? 

A.—The independent brake and air sig¬ 
nal will be lost; but by plugging the 
exhaust port of the independent brake 
valve the automatic brake may be applied 
and released in the usual manner with the 
automatic brake valve. 

Q.—Where the reducing valve pipe is 
broken, why is it necessary to plug the 
independent brake valve exhaust port that 
an automatic application of the brake 
may be made on the engine? 

A.—Where this pipe is broken, there 
will be no air pressure on top of the 
rotary in the independent brake valve to 
hold it to its seat; therefore, when an 
automatic application of the brake is 
made, pressure forming under the rotary 
valve by the air coming from the ap¬ 
plication cylinder and chamber will lift 
the rotary valve from its seat and allow 
the air in the application chamber and 
cylinder to escape to the atmosphere 
through the independent brake valve ex¬ 
haust port, thus causing the release of 
the locomotive brake. 

Dead Engine Feature 

• Q.—What is the dead engine device? 

A.—The dead engine device is nothing 
more or less than a pipe connection be- 


38 


Helpful Hints on 


tween the main reservoir pipe and the 
brake pipe. In this pipe is found a com¬ 
bined strainer ^nd check valve with a 
choke fitting and a cut-out cock, which 
when open forms a connection between 
the main reservoir pipe and brake pipe. 

Q.—What is the purpose of this device? 

A.—To provide a means of charging 
the main reservoir of an engine whose 
pump is inoperative. 

Q.—What is the object in charging the 
main reservoir of an engine with a dis¬ 
abled pump? 

A.—As the air used in applying the 
locomotive brake comes from the main 
reservoir, for the brake to be operated 
on this engine it is necessary that its 
main reservoir be charged. 

Q.—With a 70-pound brake pipe pres¬ 
sure, what pressure will be had in the 
main reservoir when using this device? 

A.—About 50 pounds. 

Q.—When the dead engine feature is 
being used, in what position should the 
automatic and independent brake valves 
be carried? 

A.—Running position. 

Q.—What should be the position of the 
brake pipe cut-out cock below the brake 
valve ? 

A.—It should be closed. 


Modern Locomotive Brakes 39 


Distributing Valve 

Q. —What is the duty of the distribut¬ 
ing valve? 

A. — To admit air from the main reser¬ 
voir to the locomotive brake cylinders 
when applying the brake, to exhaust the 
air from the brake cylinders when releas¬ 
ing the brake, to automatically maintain 
the brake cylinder pressure against leak¬ 
age, and to develop the proper brake 
cylinder pressure regardless of piston 
travel. 

Q. — To what is the distributing valve 
attached? 

A. —To the distributing valve reservoir. 

Q. — How many chambers has the dis¬ 
tributing valve reservoir? 

A/ —Two-pressure chamber and applica¬ 
tion chamber. 

Q. — Name the different pipe connec¬ 
tions to the distributing valve reservoir. 

A. — Main reservoir supply pipe, ap¬ 
plication cylinder pipe, distributing valve 
release pipe, brake cylinder pipe, and 
brake pipe. 

Q. — To what do these different pipes 
connect? 

A. — The main reservoir supply pipe, 
which is the upper pipe on the left, con¬ 
nects the distributing valve with the main 
reservoir pipe. 

The application cylinder pipe, which is 
the middle pipe on the left, connects the 
application cylinder of the distributing 


40 Helpful Hints on 

valve with the automatic and independent 
brake valve. 

The distributing valve release pipe, 
which is the lower pipe on the left, con¬ 
nects the application cylinder exhaust 
port in the distributing valve with the 
independent brake valve, and through it, 
when in running position, to the auto¬ 
matic brake valve. 

The brake cylinder pipe, which is the 
upper pipe on the right, connects the dis¬ 
tributing valve with the different brake 
cylinders on the locomotive. 

. The brake pipe branch pipe, which is 
the lower pipe on the right, connects the 
distributing valve with the brake pipe. 

Q.—Explain briefly the operation of 
the distributing valve when making an 
automatic service application of the 
brake. 

A. — When a gradual reduction of brake 
pipe pressure is made, it will be felt in 
the chamber in front of the equalizing 
piston, causing a difference of pressure 
on the two sides of the piston, which will 
cause the piston to move to application 
position. The first movement of the pis¬ 
ton closes the feed groove, also moves the 
graduating valve, uncovering the service 
port in the equalizing slide valve; this 
movement of the piston also causes the 
shoulder on the end of its stem to engage 
the equalizing slide valve, and the con¬ 
tinued movement of the piston moves the 


Modern Locomotive Brakes 41 

valve to service position, in which the 
service port in the slide valve connects 
with a port in the seat which leads to 
the application chamber and cylinder. As 
the equalizing slide valve chamber is at 
all times connected to the pressure cham¬ 
ber, air can now flow from this chamber 
to both the application chamber and 
cylinder. Pressure chamber air will con¬ 
tinue to flow to the application chamber 
and cylinder -until its pressure becomes 
slightly less than that in the brake pipe, 
when the piston and graduating valve will 
move to the left until the shoulder oil the 
piston stem strikes the slide valve; this 
movement of the graduating valve closes 
the service port, thus closing the com¬ 
munication between the pressure chamber 
and application chamber and cylinder, 
also closing the port which leads to' the 
safety valve. 

Q.—Upon what does the amount of 
pressure in the application cylinder and 
chamber depend, when making an auto¬ 
matic service application of the brake? 

A.—On the amount of brake pipe re¬ 
duction ; and as the relative volume of 
the pressure chamber and application 
cylinder and chamber is practically the 
same as that of an auxiliary reservoir 
and brake cylinder, it will be understood 
that one pound from the pressure cham¬ 
ber will make two and one-half pounds in 
the application chamber and cylinder; in 


42 


Helpful Hints on 


other words, with the pressure chamber 
charged to 70 pounds and no pressure 
in the application cylinder or chamber, 
if they were connected and allowed to 
equalize they would do so at about 50 
pounds; that is, 20 pounds from the 
pressure chamber would make 50 pounds 
in the application chamber and cylinder. 

Q.—How is the application piston af¬ 
fected by the air pressure in the applica¬ 
tion cylinder? 

A.—Pressure forming in this cylinder 
will force the piston to application posi¬ 
tion. In moving to this position it will 
carry with it the exhaust valve, closing 
the exhaust port, at the same time mov¬ 
ing the application valve, opening the 
supply port, allowing main reservoir air 
to flow to the different brake cylinders 
on the locomotive, until the pressure in 
these cylinders becomes slightly greater 
than that in the application cylinder, 
when the piston will move back, carrying 
the application valve with it, just far 
enough to close the supply port. 

Q.—With the application valve in lap 
position, if there be brake cylinder leak¬ 
age, will the locomotive brake leak off? 

A.—No; any drop in b'rake cylinder 
pressure will be felt in the chamber on 
the brake cylinder side of the application 
piston, causing a difference in pressure 
on the two sides of the piston, thus allow¬ 
ing the pressure in the application cylin- 


Modern Locomotive Brakes 43 


der to move the application piston and 
valve, again opening the supply port, al¬ 
lowing main reservoir air to flow to the 
brake cylinders until the pressure is again 
slightly greater than that in the applica¬ 
tion cylinder, when the application piston 
and valve will move back to lap position. 
Thus in this way air will be supplied to 
the brake cylinders of the locomotive, 
holding the brake applied regardless of 
brake cylinder leakage. 

Q.—What effect will the piston travel 
have on pressure developed in the brake 
cylinders I 

A.—None; as the pressure in the brake 
cylinders is dependent entirely on the 
pressure in the application cylinder, 
which is not affected by the piston travel. 

Q.—Explain the movement of the parts 
in the distributing valve when the auto¬ 
matic brake valve is moved to release 
position, after an automatic application 
of the brake. 

A.—In release position, air from the 
main reservoir flows direct to the brake 
pipe, causing a rise of pressure in the 
chamber in front of the‘equalizing pis¬ 
ton; this increase of pressure above that 
on the pressure chamber side of the pis¬ 
ton will cause the piston to move to 
release position^ carrying with it the 
-graduating and equalizing slide valves. 
In this position the application cylinder 
exhaust port is connected to the distribut- 


44 Helpful Hints on 

mg valve release pipe and on through the 
independent brake valve to the automatic 
brake valve, where the port to which this 
pipe leads is blanked by the automatic 
rotary valve, which prevents air from 
leaving the application cylinder and 
chamber, thus holding the locomotive 
brake applied while the train brakes are 
being released. 

Q. — Explain the movements of the 
parts in the distributing valve when the 
automatic brake valve is moved to run¬ 
ning position after having first been 
moved to release or holding position, fol¬ 
lowing a brake application. 

A. — In this position the port to which 
the distributing valve release pipe is con¬ 
nected at the automatic brake valve is 
open to the exhaust, thus allowing the air 
in the application cylinder and chamber 
to escape to the atmosphere. The reduc¬ 
tion of application cylinder pressure 
causes the application piston to move to 
release position, carrying with it the ap¬ 
plication valve and exhaust valve, opening 
the exhaust port, allowing the brake 
cylinder air to escape to the atmosphere, 
releasing the brake. 

Q. — Explain what takes place in the 
distributing valve when an automatic 
emergency application of the brake is 
made. 

A. — Any sudden reduction of brake, 
pipe pressure will be felt on the brake 


Modern Locomotive Brakes 45 

pipe side of the equalizing piston, and 
will cause it and the equalizing slide 
valve to move to the extreme travel, com¬ 
pressing the graduating spring. In this 
position, pressure chamber air can flow 
into the application cylinder only;, this 
will cause a quick rise of pressure in the 
application cylinder, forcing the applica¬ 
tion piston and valve to full application 
position, opening the supply port, allow¬ 
ing main reservoir air to flow to the loco¬ 
motive brake cylinders until the pressure 
in the brake cylinder is slightly greater 
than that in the application cylinder, 
when the application piston and valve will 
move back to lap position, as in a service 
application. 

Q.-—At what pressure will the pressure 
chamber and application cylinder equalize 
when using a 70-pound brake pipe pres¬ 
sure ? 

A.—At about.65 pounds; as in emer¬ 
gency position the application chamber is 
cut off. However, with the automatic 
brake valve in emergency position, there 
is a small port in the rotary valve (called 
the blow-down timing port) open to the 
application pipe and cylinder which al¬ 
lows main reservoir air to flow to the 
application cylinder, raising its pressure 
to the adjustment of the safety valve. 

Safety Valve 

Q.—At what pressure is the safety 
valve adjusted? 


Helpful Hints on 


46 


A.—At 68 pounds, except where an 
engine is being transported over the road 
light-, when it is generally adjusted to 
35 pounds. 

Q.—How would you proceed to adjust 
the safety valve? 

A.—With the pressure pumped up, 
move the automatic brake valve to 
emergency position until a brake cylinder 
pressure of 68 pounds is developed, then 
back to lap position *, next turn the regu¬ 
lating nut on the safety valve up or down, 
as may be required. 

Q.—To what is the safety valve con¬ 
nected? 

A.—The safety valve is connected to 
the application cylinder, except in service 
lap position, when it is cut off by the 
graduating valve. 

Q.—How does the safety valve prevent 
too high a pressure in the brake cylinder? 

A.—The pressure developed in the 
brake cylinders is governed by the press¬ 
ure in the application cylinder, which is 
within control of the safety valve. 

Quick-Action Cap 

Q.—What is the purpose of the quick- 
action cap, and where is it located? 

A.-—Its purpose is to assist the brake 
valve in venting the brake pipe air when 
an emergency application of the brake is 
made, and it is located on the brake pipe 
side of the distributing valve. 


Modern Locomotive Brakes 47 

Q.—Explain the operation of the quick- 
action cap. 

A.—When a sudden brake pipe reduc¬ 
tion is made, it will cause the equalizing 
piston to move quickly to its extreme 
travel, the knob on the piston striking 
the graduating stem, causing it to com¬ 
press the graduating spring, moving the 
emergency valve, opening the emergency 
port; this allows brake pipe air to flow 
past the check valve, and on to the brake 
cylinders. When the brake pipe pressure 
becomes slightly less than the brake cylin¬ 
der pressure, the check valve will seat; 
thus preventing the brake cylinder air 
flowing back to the brake pipe. When 
the brake is released, the equalizing pis¬ 
ton moving back to release position, 
the graduating spring then forces the 
emergency valve back to closed position. 

Q.—Where the quick-action cap is 
used, is there any difference in the 
method of operating the brake? 

A.—No. 

Broken Pipes 

Q.—If the main reservoir supply pipe 
to the distributing valve breaks, what 
should be done? 

A.—As this will cause a loss of main 
reservoir air, the pipe should be plugged. 

Q.—If the supply pipe breaks and is 
plugged, can the locomotive brake be ap- 


48 


Helpful Hints on 


plied in a service application? In emer¬ 
gency application? 

A. — The locomotive brake cannot be 
applied in service application, but if the 
distributing valve is- equipped with a 
quick-action cap, and an emergency ap¬ 
plication is made, the air coming from 
the brake pipe, through the quick-action 
cap will apply the brake. 

Q. — If, with the engine alone and the 
supply pipe broken, can the locomotive 
brake be applied; if so, how? 

A. — Yes; with the engine alone the 
brake can be applied, providing the dis¬ 
tributing valve is equipped with a quick- 
action cap. To apply the brake, move 
the automatic brake valve handle to 
emergency position, and then return it to 
holding position until the brake pipe is 
recharged to about 45 pounds, when the 
handle should be moved to lap position. 
The movement of the brake valve to 
emergency position causes the equalizing 
piston in the distributing valve to move 
to emergency position, and in so doing 
moves the emergency valve in the quick- 
action cap to open position, thereby cre¬ 
ating an opening from the brake pipe to 
the brake cylinders; then by admitting 
more air to the brake pipe it is free to 
flow to the brake cylinders, applying the 
brake. The end of the supply pipe 
toward the distributing valve must be 
plugged. 


Modern Locomotive Brakes 49 

Q. — If the brake pipe be recharged 
above 50 pounds, what will be the effect ? 

A. — The brake will release down to a 
pressure of about 15 pounds. 

Q.—If the distributing valve is not 
equipped with a quick-action cap, can the 
locomotive brake be operated with the 
supply pipe broken? 

A. — Yes; the locomotive, brake can be 
operated by first plugging the supply pipe 
connection to the distributing valve, also 
the distributing exhaust port; then re¬ 
move the application piston; to do this, 
it is necessary to first remove the ap¬ 
plication valve cover and take out the 
application valve and its stem, then re¬ 
place the cover; next remove the applica¬ 
tion cylinder cover and take out the 
application piston, then replace the cover. 
Desiring to apply the brake, move the 
independent brake valve to quick-applica¬ 
tion position, air coming from the re¬ 
ducing valve will flow through the ap¬ 
plication cylinder pipe to the application 
chamber and cylinder, and as the applica¬ 
tion piston is now removed, the air will 
be free to flow .to the brake cylinder port 
and to the brake cylinders, applying the 
brake. 

Q.—If the locomotive brake be applied 
in the manner just described, how may it 
be released? 

A.—By placing the independent brake 
valve in release position. 


50 Helpful Hints on 

Q.—If the application cylinder pipe 
breaks, what effect will it have on the 
locomotive brake? 

A.—The brake cannot be applied with 
either the automatic or the independent 
brake valve. 

Q.—If the application cylinder pipe 
breaks and is plugged, can the locomotive 
brake be operated? 

A.—Yes; the brake can be applied and 
released with the automatic brake valve 
in the usual manner. 

Q.—If this pipe breaks, can the loco¬ 
motive brake be applied with the inde¬ 
pendent brake valve? 

A.—This depends on where the pipe is 
broken. If the break is between the dis¬ 
tributing valve and the tee, where the 
pipe branches, one part leading to the. 
independent brake valve, the other part to 
the automatic brake valve, or between the 
tee and the independent brake valve, the 
use of the independent brake valve is 
lost; but if the break is between the tee 
and the automatic brake valve, if the pipe 
be plugged, the brake may be applied and 
released in the usual manner with the 
independent brake valve, only the blow¬ 
down timing feature is lost. 

Q.—If the distributing valve release 
pipe breaks, what will be the'effect? 

A.—The holding feature of the brake 
will be lost; that is, the locomotive brake 
will release when the automatic brake 


Modern Locomotive Brakes 51 

valve is moved to release or holding posi¬ 
tion, the same as with the old G-6 equip¬ 
ment. . 

Q.—If the release pipe breaks, should 
it be plugged? 

A.—No; as, when this pipe is plugged, 
any leakage of air into the application 
cylinder or chamber will cause the loco¬ 
motive brakes to creep on, and the creep¬ 
ing on of the brakes is so often respon¬ 
sible for the loosing of tires that any¬ 
thing which tends to bring about this 
condition should be. avoided. 

Q.—If this pipe breaks and is plugged, 
can the locomotive brake be applied and 
released ? 

A.—Yes; the brake can be applied w^ 
either the automatic or the independent 
brake valve; but it can be released only 
by placing the independent brake valve 
in release position. 

Q.—If the release pipe is broken and 
not plugged, can the independent brake 
be applied? 

A.—Yes, by placing the brake valve in 
quick-application position the brake will 
apply, but there will be a waste of air 
through the broken pipe, and the brake 
will release when the valve is returned to 
lap position. 

Q.—If the brake cylinder pipe breaks, 
can the locomotive brake be applied? 

A.—This depends on where the pipe 
breaks; if between the cut-out cock and 


52 


Helpful Hints on 


any one of the brake cylinders, close the 
cut-out cock to that cylinder, and the 
other cylinders may be used. But if the 
pipe breaks at the distributing valve, the 
locomotive brake will be lost. 

Q.—If the brake cylinder pipe breaks 
and is not plugged, as where the brake is 
inoperative, what must be done? 

A.—The cut-out cock in the main reser¬ 
voir supply pipe to the distributing valve 
must be closed. 

Q.—If the supply pipe cut-out cock is 
not closed, what will result? 

A.—There will be a great loss of main 
reservoir air through the broken pipe 
each time the train brake is applied. 

Q.—Is there any other way of prevent¬ 
ing the loss of main reservoir air through 
this broken pipe than by closing the cut¬ 
out cock in the supply pipe? 

A.—Yes; if the independent brake 
valve be held in release position, while 
the train brake is-being applied, the ap¬ 
plication piston in the distributing valve 
will remain in release position; therefore, 
there will be no waste of air. 

Q.—If the brake pipe connection to the* 
distributing valve breaks, what should be 
done? 

A.—Plug the end leading from the 
brake pipe; the locomotive brake must 
now be released by placing the indepen¬ 
dent brake valve in release position. 

Q.—If this pipe breaks and is plugged, 


Modern Locomotive Brakes 53 


can the locomotive brake be applied with 
the automatic brake valve? 

A .—-A service application of the brake 
cannot be made, as now there is no con¬ 
nection between the brake pipe and the 
distributing valve; however, if the brake 
valve handle be placed in emergency posi¬ 
tion, the blow-down timing port will be 
open to the application cylinder, thus 
causing an application of the brake. 

Q.—If the brake be applied in the man¬ 
ner just described, can it be released with 
the automatic brake valve? 

A.—No; it must be released by placing 
the independent brake valve in release 
position. 

Q.—If the brake pipe connection to the 
distributing valve breaks and is plugged, 
can the independent brake be operated? 

A.—Yes; the brake may be applied in 
the usual manner, but will have to be 
released by placing the independent brake 
valve in release position. 

Distributing Valve Defects 

Q.—If there is a blow at the distribut¬ 
ing valve exhause port when the brake 
is released, where would you look for the 
trouble ? 

A.—This would indicate a leaky ap¬ 
plication valve, or where the distributing 
valve is equipped with a quick-action 
cylinder cap, a leak past the emergency 
valve will also cause a blow at this port. 


54 Helpful Hints on 

Q.—How may it be determined which 
valve is at fault? 

A.—Reduce the brake pipe pressure to 
zero, then release the brake with the in¬ 
dependent brake valve; if the blow con¬ 
tinues, the defect will be found in the 
application valve; if the blow stops, the 
emergency valve will be at fault. 

Q.—If there be a continuous blow at 
the distributing valve exhaust port when 
the brake is applied, where would you 
look for the trouble? 

A.—This would indicate a leaky ex¬ 
haust valve. 

Q.—If the locomotive brake released 
with the automatic brake valve in lap 
position, where would you look for the 
trouble? 

A.'—Would look for a leak in the ap¬ 
plication cylinder pipe or in the applica¬ 
tion cylinder cover gasket. 

Q.—If the brake remained applied in 
lap position, but released in release or 
holding position, where would you look 
for the trouble? 

A.—Would look for a leak in the dis¬ 
tributing valve release pipe. 

Q.—If, after making a light brake ap¬ 
plication, the brake cylinder pressure con¬ 
tinued to increase to about 45 pounds, 
where would you look for the trouble? 

A.—This would indicate leakage of air 
into the application cylinder and cham¬ 
ber, coming from some source where a 


JVTodkhn Locomotive Brakes 55 


pressure of 45 pounds is maintained, 
which means from the independent brake 
valve; would therefore look for leakage 
past the rotary valve or lower body gas¬ 
ket of the independent brake valve. 

Q. — If, after making a 10-pound reduc¬ 
tion of brake pipe pressure, the brake 
cylinder pressure increased to about 50 
pounds, where woidd you look for the 
trouble? (This when using a 70 pound 
brake pipe pressure.) 

A — This would indicate leakage of 
pressure chamber air past the equalizing 
slide valve in the distributing valve. 

Q. — If, after making a light applica¬ 
tion, the brake cylinder pressure increased 
to the adjustment of the safety valve, 
where would you look for the trouble? 

A. — This trouble may be caused by 
leakage past the rotary valve or either 
of the two lower body gaskets in the 
automatic brake valve, into the applica¬ 
tion cylinder pipe. 

Q. — If the distributing valve release . 
pipe and application cylinder pipe were 
crossed, what would be the effect? 

A. — A brake application made by the 
automatic brake valve cannot be released 
by the independent brake valve. 

Q. — If the safety valve leaks, what will 
be the effect? 

A. — This rnay prevent the brake apply¬ 
ing, and in an independent application 
if the brake does apply, it will release 


56 


Helpful Hints on 


when the brake valve is returned to lap 
position. 

Locomotive Brake Creeps On 

Q.—If the locomotive brake creeps on 
with the automatic and independent brake 
valves in running position, where would 
you look for the trouble? 

A.—This is caused by a variation of 
brake pipe pressure due either to a non¬ 
sensitive feed valve or an overcharged 
brake pipe, which causes the equalizing 
piston and slide valve in the distributing 
valve to move to application position, 
making an automatic application of the 
brake. 

Q.—If the locomotive brake creeps on, 
how should it be released? 

A.—By moving the automatic brake 
valve handle to release position and re¬ 
turning it immediately to running posi¬ 
tion. 

Q.—Why not make the release with the 
independent brake valve? 

A.-—Where the brake is released with 
the independent brake valve, the equaliz¬ 
ing piston and its slide valve are not 
moved to release position, therefore the 
brake would immediately reapply. 


Modern Locomotive Brakes 57 


NEW YORK L-T EQUIPMENT 

Q -—On what is this brake designed to 
operate ? 

A.—On engine and tender. 

Q.—What are some of the advantages 
of the L-T equipment over older types of 
locomotive brakes? 

A.—May be used on engines in any 
class of service. Brake cylinder pressure 
not affected by piston travel or leakage; 
locomotive brake may be applied or re¬ 
leased independent of the train brake; 
brakes on the second engine of a double- 
header may be applied or released in¬ 
dependent of the brakes on the leading 
engine or train. 

Q.—Name the different parts of the 
equipment, and explain in a general way 
their duties. 

A.—1. The air pump, to compress the 
air used on the locomotive and cars. 

2. The duplex governor, to control the 
pump when the desired pressure is ob¬ 
tained in the main reservoir. 

3. The main reservoir, in which to 
store'a large volume of air for the prompt 
charging and recharging of the brakes, 
and to collect the moisture and dirt in the 
air. 

4. The main reservoir cut-out cock, 
which, when closed, cuts off the com¬ 
munication between the main reservoir 
and the brake system. 


58 


Helpful Hints on 


5. The automatic brake valve, to oper¬ 
ate the locomotive and train brake. 

6. The equalizing reservoir, to furnish 
the proper volume of air above the equal¬ 
izing piston. 

7. The special release valve, to release 
the locomotive brakes after an automatic 
application, independent of the train 
brakes. 

8. The double-throw check valve, to 
form a dividing line in the brake cylinder 
pipe between the control valve and in¬ 
dependent brake valve. 

9. The independent brake valve, to 
operate the locomotive brake independent 
of the train brake. 

10. The feed valve, to regulate the 
brake pipe pressure, when the automatic 
brake valve is in running or holding posi¬ 
tion. 

11. The reducing valve, to regulate the 
pressure in the independent brake valve 
and signal line. 

12. The control valve, its reservoir and 
safety valve, to admit air to and from 
the brake cylinders on the locomotive, 
when applying and releasing the brakes, 
and to control the pressure within the 
prescribed limits, in all automatic ap¬ 
plications. 

13. Two duplex air gauges, one to in¬ 
dicate main reservoir and equalizing 
reservoir pressures, the other to indicate 


Modern Locomotive Brakes 59 


brake pipe pressure and locomotive brake 
cylinder pressure. 

14. The dead engine feature, by which 
air may be supplied to the main reservoir 
of an engine, the pump of which is in¬ 
operative. 

The above, with the necessary brake 
cylinders, air strainers, cut-out cocks, 
hose couplings and piping, go to make 
up the L-T equipment. 

Q.—Commencing at the air pump, 
name the different pipes and their con¬ 
nections. 

A.—Discharge pipe, to connect the 
pump to the first main reservoir. 

Connecting pipe, to connect the two 
main reservoirs. 

Main reservoir pipe, to connect the sec¬ 
ond main reservoir with the maximum 
pressure head of the pump governor, con¬ 
trol valve, feed valve, reducing valve, and 
automatic brake valve. This pipe also 
furnishes air to the connections of all 
other air-operated appliances on "the loco¬ 
motive. 

Feed valve pipe, to connect the feed 
valve with the automatic brake valve. 

Excess pressure pipe, to connect the 
feed valve pipe to the chamber above the 
diaphragm in the excess pressure head of 
the pump governor. 

Excess pressure operating pipe, to con¬ 
nect the automatic brake valve to the 


60 


Helpful Hints on 


chamber below the diaphragm in the ex¬ 
cess pressure head of the pump governor. 

Maximum pressure head pipe, to con¬ 
nect the maximum pressure head of the 
governor to the main reservoir pipe. 

Reducing valve pipe, to connect the re¬ 
ducing valve with the air signal line and 
independent brake valve. 

Brake pipe, to connect the automatic 
brake valve with the control valve and 
train brakes. 

Brake cylinder pipe, to connect the con¬ 
trol valve and independent brake valve 
with the different brake cylinders on the 
locomotive. 

Control reservoir pipe, to * connect the 
control reservoir of the control valve with 
the automatic brake valve and special 
release valve. 

Automatic control valve release pipe, to 
connect the control reservoir exhause port 
with the automatic brake valve. 

Continuous feed pipe, to connect the 
reducing valve pipe to the auxiliary 
reservoir in the automatic control valve. 

Duplex Pump Governor 

Q.—Explain the operation of the pump 
governor. 

. A.—As the governor used with the L-T 
equipment is the same in principle of 
operation as that described in the E-T 
equipment, no further description will be 
given here. 


Modern Locomotive Brakes 61 

Duplex Air Pumps 

Q.—How many different size pumps 
are made by the New York Air Brake 
Company ? 

A.—Four; they are known as Numbers 
1, 2, 5 and 6. 

Q.—What are the dimensions of these 
pumps? 

A.—The dimensions are as follows: 



Diam. 

Diam. 

Diam. 


Pump 

of steam 

of L. P. 

of H. P. 


No. 

cyl. 

air cyl. 

air cyl. 

Stroke 

1 

5 in. 

7 in. 

5 in. 

9 in. 

2 

7 in. 

10 in. 

7 in. 

9 in. 

5 

8 in. 

12 in. 

8 in. 

12 in. 

6 

7 in. 

11 in. 

7 in. 

10 in. 


Q.—Name the different cylinders of the 
pump. 

A.—The two lower are known as stem 
cylinders; the two upper as the low pres¬ 
sure and high pressure air cylinders. 

Steam End of Pump 

Q.—Of what does the valve gear of 
these different pumps consist? 

A.—Of two ordinary D slide valves in 
the older make of pumps, while a later 
type has piston valves; these valves are 
actuated by tappet rods, which extend 
into the hollow piston rods, and are 
moved by the tappet plates, which are 
fastened to the steam piston heads. 

Q.—How is the admission and exhaust 
of steam controlled? 



G2 Helpful Hints on 

A.—The valve under one cylinder con¬ 
trols the admission of steam to and from 
the opposite cylinder, so that when one 
piston is moving the other is at rest. 

Q.—How should the pump be started? 

A.—Before turning on steam, the drain 
cocks should be open and left so until the 
pump is warm and the water of condensa¬ 
tion worked out. No provision is made 
in the steam end to cushion the pistons 
at the end of the stroke; for when work¬ 
ing against pressure the air in the air 
cylinders acts as a cushion. When the 
pump is first started, there is no air in 
the main reservoir, and consequently there 
is nothing to prevent the pistons from 
striking the cylinder heads if the pump 
be started quickly. Therefore, the pump 
should be started slowly until a pressure 
of 30 or 40 pounds is accumulated in the 
main reservoir to cushion the pistons, 
when the throttle may be opened wide 
enough to run the pump at the required 
speed. The drain cocks should then be 
closed and the lubricator started and 
allowed to feed freely until eight or ten 
drops have passed to the pump; the feed 
should then be reduced to an amount suf¬ 
ficient for proper lubrication. 

Air End of Pump 

Q.—How many air valves in each of 
the No. 1 and No. 2 pumps? 

A.—Six, namely: one upper and one 


Modern Locomotive Brakes 63 

lower receiving valve, one upper and one 
lower intermediate discharge valve, and 
one upper and one lower final discharge 
valve. 

Q.—How many air valves in each of the 
No. 5 and No. 6 pumps? 

A.-^Eight, namely: one upper and one 
lower receiving valve for the low pres¬ 
sure air cylinder, one upper and one 
lower intermediate discharge valve, one 
upper and one lower receiving valve for 
the high pressure cylinder, and one upper 
and one lower final discharge valve. 

Q.—What should be the lift of the dif¬ 
ferent air valves? 

A.—In the No. 1 and No. 2 pumps all 
valves should have ^ inch lift; in the 
No. 5 and No. 6 all valves should have 
1 % inch lift. 

Q.—Explain the operation of the air 
end of the pump. 

A.—As the piston in the low pressure 
cylinder moves up, a partial vacuum is 
formed below it,, and air from the at¬ 
mosphere enters past the lower receiving 
valve, filling this end of the cylinder with 
air at atmospheric pressure. In the 
meantime, the air above the piston, being- 
compressed, will hold the upper receiving 
valve to its seat, and lifts the upper in¬ 
termediate discharge valve from its seat, 
allowing the air to pass from the low to 
the high pressure cylinder. The high- 
pressure piston now moving up causes a 


64 


Helpful Hints on 


partial vacuum to be formed below it, 
and air from the atmosphere flows 
through the lower receiving valve of the 
high pressure cylinder, filling this end of 
the cylinder with air at about atmospheric 
pressure. The air above the piston being 
compressed, holds the upper intermediate 
valve to its seat, and lifts the upper final 
discharge valve, allowing the air to pass 
to the main reservoir. The action is the 
same on the down stroke, only the op¬ 
posite valves are used. It may be seen 
from this that the air valves are nothing 
more or less than a set of check valves, 
which permit the air to pass in one direc¬ 
tion, but prevent its return. 

Defects of the Pump 

Q.—If a ‘ receiving valve' to the low 
pressure air cylinder breaks or sticks 
open, what effect will it have on the 
pump, and how may it be located? 

A.—No air will be compressed by the 
low pressure cylinder, as the piston moves 
toward the defective valve, and may be 
located by noting the movement of the 
low pressure piston, as the movement will 
be much quicker toward the defective 
valve than the opposite stroke. Air will 
blow back to the atmosphere as the piston 
moves toward the defective valve, and 
may be detected by holding the hand over 
the strainer. 

Q.—If an intermediate discharge valve 


Modern Locomotive Brakes 65 


breaks or sticks open, what effect will it 
have on the pump, and how may it be 
located? 

A.—If an intermediate discharge valve 
breaks or sticks open, no air will be com¬ 
pressed by that end of the pump where 
is located the defective valve, as the air 
will flow back and forth from the high 
to the low pressure cylinders; no air will 
be taken in from the atmosphere through 
either of the strainers, as the pistons 
move from the defective valve. 

Q.—If a receiving valve to the high 
pressure air cylinder breaks or sticks 
open, what effect will it have on the 
pump, and how may it be located? 

A.—No air will be compressed by that 
end of the pump where is located the 
defective valve, as the air from both 
cylinders will be free to return to the 
atmosphere through the broken valve. 
Both pistons will make a quicker stroke 
when moving in the direction of the de¬ 
fective valve. Air will blow back to the 
strainer of the high pressure cylinder, as 
each piston moves toward the defective 
valve. 

Q.—If the final discharge valve breaks, 
what effect will it have on the pump? 

A.—If a final discharge valve breaks, 
main reservoir air will be free to return 
to the high-pressure cylinder as the high 
pressure piston moves from the defective 
valve; therefore, no air will be taken in 


66 


Helpful Hints on 


through, the receiving valve of the high 
pressure air cylinder at the end where is 
located the defective valve. The low 
pressure piston will make a slow stroke 
toward the defective valve and a normal 
stroke from it; while the high pressure 
piston will make a slow stroke toward the 
defective valve and a quick stroke from 
it, being assisted in the latter movement 
by the main reservoir air acting on the 
piston. Defective air valves may gen¬ 
erally be located by noting the temper¬ 
ature of the valve chamber in which they 
are located. 

Q.—What may be done if the receiving 
valve to the low pressure cylinder inter¬ 
mediate or final discharge valve breaks? 

A.—As all valves are of the same size 
and have the same lift, the broken valve 
may be replaced by one of the receiving 
valves of the high pressure cylinder. 
Then, by blocking the opening made by 
the removal of this receiving valve, the 
pump will be practically restored to its 
maximum efficiency. 

Q.—Can this be done with the No. 1 
and No. 2 pumps? 

A.—No; as the No. 1 and No. 2 pumps 
have no receiving valves in the high pres¬ 
sure cylinder which takes air direct from 
the atmosphere. 

Q.—What will cause a pump to pound? 

A.—The pump loose on its bracket, 
bracket loose on the boiler, nuts loose on 


Modern Locomotive Brakes 67 


the air ends of the pistons, air valves hav¬ 
ing too much lift, water in the steam 
cylinders, or running the punjp too fast 
before a sufficient pressure is accumulated 
in the main reservoir to cushion the pis¬ 
tons at the end of the stroke. 

Q.—What will cause the pump to run 
hot? 

A.—Running the pump too fast; work¬ 
ing against high pressure; air piston 
packing rings leaking; air cylinders 
worn; air passages in pump or discharge 
pipe partially stopped up; air valves 
leaking; air valves stuck shut; or lack 
of lubrication. 

Q.—If, when steam is first turned on, 
the steam piston at the right moves up 
and the pump stops, where would you 
look for the trouble? 

A.—This would indicate a loose or 
worn tappet plate, tappet rod broken, or 
the button on the end of the rod worn, in 
the cylinder at the right, or the nuts off 
the low-pressure air piston rod. 

Q.—If both pistons make a stroke up 
and the pump stops, what may be the 
cause ? 

A.—Loose or worn tappet plate on the 
piston at the left, or this tappet rod 
broken, or the button on the end of the 
rod worn, or the nuts off the high pres¬ 
sure air piston rod. 

Q.—If both pistons make a stroke up 
and the piston at the right a stroke down 


68 


Helpful Hints on 


and the pump stops, what may be the 
trouble? 

A.—This would indicate a worn tappet 
plate or. the shoulder on the tappet rod 
in the cylinder at the right being worn 
so that the plate will pass over the tappet 
rod. 

Q.—If both pistons make a stroke up 
and a stroke down and the pump stops, 
what may be the cause? 

A.—This would indicate a worn tappet 
plate or shoulder on the tappet rod in 
the cylinder at the left. 

Q.—If the pump stops, how may it 
sometimes be started? 

A.—First, open the drain cock to learn 
if the steam is passing the governor; if 
it is, jar the steam head lightly; failing 
to start, close the throttle for a short 
time, then open it quickly; this will in¬ 
variably start the pump where the cause 
of stopping was due to lack of lubrica¬ 
tion. 

Q.—How should the air end of the 
pump be oiled, and what grade of oil 
should be used? 

A.—Oil should be used sparingly in the 
low pressure cylinder, but more is re¬ 
quired in the high pressure cylinder, 
owing to higher temperature. A good 
quality of valve oil should be used. 

Q.—How will the steam end of the 
pump be affected by the use of too much 
oil? 


Modern Locomotive Brakes 69 

A.—This may cause the pump to short- 
stroke or “dance,’ ; especially where the 
piston type of valves is used. 

Type “L” Automatic Brake 
Valve 

Q.—What type of brake valve is used 
with the L-T equipment? 

A.-—The automatic brake valve known 
as the type L valve; it is of the rotary 
valve type, and is the same valve, port 
for port, as that used with the B-T equip¬ 
ment, and the same results should be ob¬ 
tained in the different positions as with 
the H-6 brake valve; therefore, no fur¬ 
ther description need be given here. 

Double Pressure Feed Valve 

Q.—What type of feed valve is used 
with the L-T equipment? 

A.—The same type of valve is used as 
with the E-T equipment; therefore re¬ 
quires no further description here. 

Independent Brake Valve 

Q.—What type of valve is used as an 
independent brake valve with this equip¬ 
ment? 

A.—This valve is of the slide valve 
type. 

Q.—What is the duty of the indepen¬ 
dent brake valve? 

A.—By its use the locomotive brake 


70 


Helpful Hints on 


may be applied and released independent 
of the train brake. 

Q.—Name the different positions of 
this valve. 

A.—Release, lap, service, and emer¬ 
gency positions; and in the latter type 
of valve a new position has been added, 
known as locomotive release position. 

Q.—What is the purpose of release 
position ? 

A.—This is the position in which the 
handle should be carried when not in use. 
In this position the brake cylinder pipe, 
on the straight air side of the double 
check valve, is connected with the exhaust 
through a cavity in the slide valve. 

Q.—What is the purpose of service 
position? 

A.—In this position a small opening is 
made in the application port through 
which air can pass to the locomotive brake 
cylinders, applying the brake gradually. 

Q.—What is the purpose of emergency 
position ? 

A.—In this position a full opening of 
the application port is had, allowing the 
air to flow rapidly from ‘the reducing 
valve pipe to the locomotive brake cylin¬ 
ders, thus securing a quick application of 
the brake. 

Q.—What is the purpose of locomotive 
release position? 

A.—When the handle is moved to this 
position, any air in the control reservoir 


Modern Locomotive Brakes 71 


of the control valve is free to escape to 
the atmosphere, thus securing an inde¬ 
pendent release, following an automatic 
application, of the locomotive brake. 

Q.—What brake cylinder pressure is 
developed by this brake? 

A.—About 45 pounds. 

Q.—How is this and signal line pres¬ 
sure regulated? 

A.—By the reducing valve, which is 
practically the same in its operation as 
the feed valve already described. 

Automatic Control Valve 

Q.—What is the duty of the control 
•valve ? 

A.—To admit air from the main reser¬ 
voir to the locomotive brake cylinders, 
when applying the brake; to exhaust the 
air from the brake cylinders, when releas¬ 
ing the brake; to automatically maintain 
the brake cylinder pressure against leak¬ 
age, and to develop the proper brake 
cylinder pressure regardless of piston 
travel, in all automatic applications of 
the brake. 

Q.—To what is the control valve at¬ 
tached ? 

A.—To a double chamber reservoir. 

Q.—Name these chambers. 

A.—Auxiliary reservoir and control 
reservoir. 

Q.—Name the different pipe connec¬ 
tions to the control reservoir. 


72 


Helpful Hints on 


A.—The upper pipe at the left, when 
facing the control valve, is the brake pipe 
connection; the lower pipe at the left, 
the brake cylinder pipe; the upper pipe 
at the right, the release pipe; the middle 
pipe at the right, the main reservoir sup¬ 
ply pipe; the lower pipe at the right, the 
control reservoir pipe; the pipe con¬ 
nected to and in the middle of the reser¬ 
voir, the continuous feed pipe. 

Q.-—To what do these different pipes 
connect? 

A.—The brake pipe branch pipe, which 
is the upper pipe on the left, connects the 
control valve with the brake pipe. 

The brake cylinder pipe, which is the 
lower pipe on the left, connects the con¬ 
trol valve with the different brake cylin¬ 
ders on the locomotive. 

The control release pipe, which is the 
upper pipe on the right, connects the 
control cylinder, through the slide valve, 
to the automatic brake valve. 

The main reservoir supply pipe, which 
is the middle pipe on the right, connects 
the control valve with the main reservoir 
pipe. 

The control reservoir pipe, which is the 
lower pipe on the right, connects the con¬ 
trol reservoir with the automatic brake 
valve and the special release valve. 

The continuous feed pipe, which is con¬ 
nected at the left side of the double 


Modern Locomotive Brakes 73 

chamber reservoir, connects the auxiliary 
reservoir with the reducing valve pipe. 

Q.—Explain the operation of the con¬ 
trol valve when making an automatic 
service application of the brake. 

A.—When a gradual reduction of brake 
pipe pressure is made, it will be felt in 
the chamber above the triple piston, caus¬ 
ing a difference in pressure on the two* 
sides of the piston, which wili cause it 
to move upward to application position. 
The first movement of the piston closes 
the feed groove, also moves the graduat¬ 
ing valve, uncovering the service port in 
the slide valve; and the continued move¬ 
ment of the piston moves the slide valve 
to service position, in which the service 
port in the slide valve connects with the 
port leading to the control reservoir. As 
the slide valve chamber and auxiliary 
reservoir are connected at all times, air 
can now flow from the auxiliary reser¬ 
voir to the control cylinder and reservoir. 

Q.—How long will the air continue to 
flow from the auxiliary reservoir to the 
control cylinder and reservoir? 

A.—Until the pressure on the auxiliary 
reservoir side of the piston becomes 
slightly less than that on the brake pipe 
side of the piston, when the piston and 
graduating valve will move down until 
the shoulder on the piston strikes the 
slide valve; this movement of the grad¬ 
uating valve closes the service port, thus 


74 Helpful Hints on 

closing the communication between the 
auxiliary reservoir and control cylinder 
and reservoir, also closing the port which 
leads to the safety valve. 

Q.—Upon what does the amount of 
pressure in the control cylinder and reser¬ 
voir depend when making an automatic 
service application of the brake? 

A.—On the amount of brake pipe re¬ 
duction; and as the relative volume of 
the auxiliary reservoir and control reser¬ 
voir is as 2*4 is to 1 it will be under¬ 
stood that one pound from the auxiliary 
reservoir will make 2*4 pounds in the 
control cylinder and reservoir. In 
other words, with the auxiliary reservoir 
charged to 70 pounds, and no pressure in 
the control cylinder or reservoir, if they 
were connected the pressure would equal¬ 
ize at 50 pounds; that is, 20 pounds from 
the auxiliary reservoir will make 50 
pounds in the control cylinder and reser¬ 
voir. 

Q.—How is the application piston in 
the control valve affected by the air pres¬ 
sure in the control cylinder? 

A.—Pressure in this cylinder will force 
the piston downward or to application 
position. The piston in moving will carry 
with it the exhaust valve, closing the ex¬ 
haust port, and at the same time unseat 
the application valve, thus allowing main 
reservoir air to flow to the brake cylin¬ 
ders on the locomotive. 


Modern Locomotive Brakes 75 

Q.—How long will the air continue to 
flow to the brake cylinders? 

A.—Until the pressure in the brake 
cylinders becomes slightly greater than 
that in the control cylinder, when the 
application piston will be moved up just 
far enough to allow the application valve 
to be seated. 

Q.—With the application valve closed, 
if there be brake cylinder leakage will 
the locomotive brake leak off? 

A.—No; as any drop in brake cylinder 
pressure will be felt in the chamber be¬ 
low the application piston, causing a dif¬ 
ference in pressure on the two sides of 
the piston, thus allowing the pressure in 
the control cylinder to move the piston 
down, again unseating the application 
valve, allowing a further flow of main 
reservoir air to the brake cylinders, until 
the pressure is again slightly greater than 
that in the control cylinder, when the 
piston will move up, allowing the applica¬ 
tion valve to close. Thus in this way air 
will be supplied to the brake cylinders of 
the locomotive, holding the brakes ap¬ 
plied regardless of leakage. 

Q.—What effect will the piston travel 
have on the pressure developed in the 
brake cylinders? 

A.—None; as the pressure in the brake 
cylinders is dependent entirely on the 
pressure in the control cylinder, which is 
not affected by piston travel. 


76 Helpful Hints on 

Q.—Explain tlie movements of the 
parts in the control valve, when the auto¬ 
matic brake valve is moved to release 
position, following an automatic applica¬ 
tion of the brakes. 

A.—In release position air from the 
main reservoir flows direct to the brake 
pipe, causing an increase of pressure 
which is felt in the chamber on the brake 
pipe side of the triple piston; this in¬ 
crease of pressure will cause the piston 
to move down, carrying with it the grad¬ 
uating valve and slide valve to release 
position. This allows air from the con¬ 
trol cylinder and reservoir to flow to the 
control valve release pipe and on to the 
automatic brake valve, where the port to 
which this pipe leads is blanked by the 
automatic rotary valve, which prevents 
the air from leaving the control cylinder 
and reservoir, thus holding the locomotive 
brakes applied while the train brakes are 
being released. 

Q.—Is the action similar where the re¬ 
lease is made in holding position? 

A.—Yes; only the air for the recharge 
of the brake pipe comes through the feed 
valve instead of the large ports in the 
brake valve. 

Q.—Explain the movements of the 
parts in the control valve when the auto¬ 
matic brake valve is moved to running 
position, after having first been moved to 
release or holding, position. 


Modern Locomotive Brakes 77 

A.—In this position of the brake valve, 
the port to which the control valve re¬ 
lease pipe is connected is open to the 
exhaust through the automatic brake 
valve, thus allowing the air in the con¬ 
trol cylinder and reservoir to escape to' 
the atmosphere, causing a release of the 
'locomotive brake. 

Q.—Explain what takes place in the 
control valve when an automatic emer¬ 
gency application of the brake is made. 

A.—Any sudden reduction of brake 
pipe pressure will be felt on the brake 
pipe side of the triple piston, and will 
cause the piston and its slide valve to 
move to their extreme travel, compressing 
the graduating spring. In this position 
auxiliary reservoir air can flow past the 
end of the slide valve to the control cylin¬ 
der and reservoir, forcing the application 
piston and valve to application position, 
allowing main reservoir air to flow to the 
brake cylinders, until the pressure in the 
brake cylinders is slightly greater than 
that in the control cylinder, when the 
control piston will be forced upward, al¬ 
lowing the application valve to seat. 

Q.—When using a 70-pound brake pipe 
pressure, what pressure will be developed 
in the control cylinder and reservoir when 
an emergency application of the brake is 
made? 

A.—About 50 pounds. However, with 
the automatic brake valve in emergency 


78 


Helpful Hints on 


position, there is a small port in the 
rotary valve (called the blow-down timing 
port) open to the control reservoir pipe 
and to the control cylinder and reservoir, 
admitting main reservoir air to these 
chambers, building up the pressure, to 
the adjustment of the safety valve. 

Safety Valve 

Q.—At what pressure is the safety 
valve adjusted? 

A.—At 68 pounds, except when an en¬ 
gine is being transported over the road 
light, when it is generally adjusted to 35 
pounds. 

Q.—How would you proceed to adjust 
the safety valve? 

A.—With the pressure pumped up, 
move the automatic brake valve to emer¬ 
gency position until a brake cylinder pres¬ 
sure of 68 pounds is developed, then 
back to lap position; next remove the 
cap nut on the safety valve and turn the 
regulating nut up or down as may be 
required. 

Q.—To what is the safety valve con¬ 
nected? 

A.—To the control cylinder and reser¬ 
voir. 

Q.—Is the safety valve connected to 
the control cylinder and reservoir at all 
times? 

A.—Yes; except in service lap posi- 


Modern Locomotive Brakes 79 

tion, when it is cut off by the graduating 
valve. 

Quick-Action Cap 

Q.—What is the purpose of the quick- 
action cap, and where is it located? 

A.—Its purpose is to assist the brake 
valve in venting the brake pipe air when 
an emergency application of the brake 
is made; it is located on the brake pipe 
side of the control valve. 

Q.—Explain the operation of the quick- 
action cap. 

A.—When a sudden brake pipe reduc¬ 
tion is made, it will cause the triple pis¬ 
ton to move upward its full travel; the 
knob on the piston striking the graduat¬ 
ing stem, causing it to compress the 
graduating spring, moving the emergency 
valve, opening the emergency port; this 
allows brake pipe air to flow against the 
nonreturn check valve, unseating it, then 
through a port to the brake cylinders. 

Q.—What is the purpose of the non¬ 
return check valve? 

A.—To close the communication be¬ 
tween the brake pipe n nd brake cylinders 
when the pressure equalizes. 

Q.—Explain the movements of the 
parts when the brake is released. 

A.—When the brake pipe is recharged, 
the triple piston returns to release posi¬ 
tion, the graduating spring then forces 
the graduating stem and emergency valve 


80 Helpful Hints on 

to their normal position, closing the emer¬ 
gency port. 

Q.—Where the quick-action cap is used, 
is there any difference in the method of 
operating the brakes? 

A.—No; the brakes should be handled 
in the same manner as with the plain 
cap. 

Dead Engine Feature 

Q.—What is the dead engine device, as 
used with the L-T equipment? 

A.—The dead engine device, as used 
with this equipment, is the same as that 
used with the E-T equipment; therefore 
should be operated in a similar manner. 

Broken Pipes 

Q.—If the pipe leading to the equaliz¬ 
ing reservoir breaks, what should be 
done? 

A.—Blank the broken pipe by placing 
a blind gasket in the connection at the 
brake valve, plug the brake pipe service 
exhaust port, and use the valve carefully 
in emergency position when making serv¬ 
ice stops. 

Q.—If the pipe connecting the feed 
valve to the automatic brake valve breaks, 
what may be done? 

A.—If this pipe breaks, plug the end 
toward the brake valve and back off on 
the regulating nut in the feed valve—this 
to stop the flow of air. The brake valve 


Modern Locomotive Brakes 81 


handle will now have to be carried in 
release position, to admit air to the brake 
pipe, and as this will allow main reser¬ 
voir pressure in the brake pipe, the max¬ 
imum pressure head of the pump governor 
should be adjusted to the pressure de¬ 
sired in the brake pipe. 

Q.—If the brake valve be carried in 
release position, will there not be a tend¬ 
ency for the locomotive brake to creep 
on? 

A.—Yes; but this trouble may be over¬ 
come by disconnecting the release pipe at 
the control valve. 

Q.—If the main reservoir supply pipe 
to the automatic control valve breaks, 
what should be done? 

A.—As this will cause a loss of main 
reservoir air, the pipe should be plugged. 

Q.—If the supply pipe breaks, can the 
locomotive brake be applied in a service 
application? In an emergency applica¬ 
tion? 

A.—The locomotive brake cannot be 
applied in an automatic' service applica¬ 
tion; but if the control valve be equipped 
with a quick-action cap and an emer¬ 
gency application is made, the air vented 
from the brake pipe to the brake cylin¬ 
ders will apply the brake. 

Q.—With the engine alone, where the 
brake pipe volume is small, if the supply 
pipe breaks, can the brake be applied? 

A.—Yes, with the engine alone, the 


82 


Helpful Hints on 


brake can be applied, providing the con¬ 
trol valve is equipped with a quick-action 
cap. To apply the brake, move the auto¬ 
matic brake valve to emergency position, 
then return it to holding position, until 
the brake pipe is recharged to about 40 
pounds, when the handle should be moved 
to lap position. The movement of the 
brake valve to emergency position causes 
the triple piston in the control valve to 
move upward, the knob on the piston 
striking the graduating stem, causing it 
to move the emergency valve, opening 
the emergency port, allowing brake pipe 
air to flow to the brake cylinders; then 
by returning the brake valve to holding 
position, admitting air to the brake pipe, 
it will be free to flow to the brake cylin¬ 
ders, applying the brake. 

Q.—What will be the effect if the con¬ 
trol release pipe breaks? 

A.—The holding feature of the brake 
will be lost; that is, the brake will release 
when the automatic brake valve is re¬ 
turned to release position. 

Q.—If the control release pipe breaks, 
should it be plugged? 

A.—No; as when this pipe is plugged, 
any air leaking into the control cylinder 
will cause the locomotive brakes to creep 
on, which is often responsible for loosen¬ 
ing of tires, and that which tends to 
bring about this condition should be 
avoided. 


Modern Locomotive Brakes 83 

Q.—-If the control release pipe breaks 
and is plugged, how can the locomotive 
brake be released after an automatic ap¬ 
plication? 

A.—By holding the special release 
valve in .release position. 

Q.—If the brake cylinder pipe breaks, 
can the locomotive brake be applied with 
the automatic brake valve? 

A.—This depends on where the pipe 
breaks; if between the cut-out cock and 
any one of the brake cylinders, close the 
cut-out cock to that cylinder, and the 
other cylinders may be used. But if the 
pipe breaks at the control valve, the auto¬ 
matic brake on the locomotive will be 
lost. 

Q.—If the brake cylinder pipe breaks 
and is not plugged, as when the brake 
is inoperative, what must be done? 

A.—The cut-out cock in the supply pipe 
must be closed. 

Q.—If the supply pipe cut-out cock is 
not closed, what will result? 

A.—There will be a great loss of main 
reservoir air through the broken pipe* 
when the train brake is applied. 

Q.—If the cut-out cock in the main 
reservoir supply pipe is not closed, how 
may this waste of main reservoir air 
through the broken pipe be overcome? 

A.—By holding the special release 
valve in open position when an automatic 


84 


Helpful Hints on 


application of the brake is being made 
on the train. 

Q.—If the brake pipe connection to the 
control valve breaks, what should be 
done? 

A.—Ping the end leading from the 
brake pipe; the locomotive brake must 
now be released with the special release 
valve. 

Q.—If the brake pipe connection 
breaks and is plugged, can the locomotive 
brake be applied with the automatic 
brake valve? 

A.—The locomotive brake cannot be 
applied with a service application as now 
there is no connection between the brake 
pipe and control valve. However, if the 
brake valve handle be placed in emer¬ 
gency position, the blow-down timing 
port will be open to the control cylinder 
through the control reservoir pipe, thus 
admitting air to this cylinder, which in 
turn moves the application piston and 
valve to application position, allowing 
main reservoir air to flow to the brake 
cylinders, applying the brake. 

• Q.—If the control cylinder pipe breaks, 
what effect will it have on the locomotive 
brake ? 

A.—The brake will not apply; or, if it 
does, will not remain applied in an auto¬ 
matic application. 

Q.—If this pipe breaks and is plugged, 
can the locomotive brake be applied? If 


Modern Locomotive Brakes 85 

so, can it be released with the special 
release valve? 

A.—Yes, the locomotive brake can be 
applied and released with the automatic 
brake valve in the usual manner. If the 
break in the pipe is between the control 
valve and the tee where the pipe branches, 
one part leading to the special release 
valve, the other part to the automatic 
brake valve, or between the tee and spe¬ 
cial release valve, the use of the special 
release valve is lost; but if the break is 
between the tee and the automatic brake 
valve, the brake may be released in the 
usual manner with this valve. 

Q.—What will be the effect if the con¬ 
tinuous feed pipe breaks? 

A.-—If this, pipe breaks, it will cause 
a loss of air from both the reducing valve 
pipe and auxiliary reservoir of the con¬ 
trol valve; therefore, both ends of the 
pipe must be plugged. 

Q.—If any of the pipes here enumer¬ 
ated break, will it in any way affect an 
independent application of the brake? 

A.-—No; as the independent and auto¬ 
matic are entirely separate from each 
other; that is, the automatic control 
valve is not brought into use when an 
independent application of the brake is 
made. However, if the brake cylinder 
pipe breaks between the double-throw 
check valve and the brake cylinders, the 
independent brake cannot be applied. 


86 


Helpful Hints on 


Control Valve Defects 

Q.—If there is a blow at the control 
reservoir exhaust port when the brake is 
released, where would you look for the 
trouble? 

A.—This would indicate a leaky ap¬ 
plication valve, or where the control valve 
is equipped with a quick-action cylinder 
cap, a leak past the emergency valve will 
also cause a blow at this port. 

Q. —How may it be determined which 
valve is at fault? 

A.—Seduce the brake pipe pressure to 
zero, then release the brake with the spe¬ 
cial release valve; if the blow continues, 
the defect will be found in the applica¬ 
tion valve; if the blow stops, the emer¬ 
gency valve will be at fault. 

Q.- —If there be a continuous blow at 
the control valve exhaust port when the 
brake is applied, where would you look 
for the trouble? 

A.—This would indicate a leaky ex¬ 
haust valve. 

Q. — If the locomotive brake released 
with the automatic brake valve in lap 
position, where would you look for the 
trouble ? 

A. —Would look for a leak in the con¬ 
trol reservoir pipe or special release valve. 

Q.—If the brake remained applied in 
lap position, but released in release or 
holding position, where would you look 
for the trouble? 


Modern Locomotive Brakes 87 

A.—Would look for a leak in the con¬ 
trol valve release pipe. 

Q.—If, after making a 10-pound reduc¬ 
tion of brake pipe pressure, the brake 
cylinder pressure increased to about 50 
pounds, where would you look for the 
trouble? (This when using a 70-pound 
brake pipe pressure.) 

A.—This would indicate leakage of 
auxiliary reservoir air past the triple 
slide valve into the control reservoir. 

Q.—If, after making a light applica¬ 
tion, the brake cylinder pressure increased 
to the adjustment of the safety valve, 
where would you look for the trouble? 

A.—This trouble may be caused by 
leakage past the rotary valve, or either 
of the two lower body gaskets in the 
automatic brake valve, into the control 
reservoir pipe. 

Q.—If the control reservoir pipe and 
release pipe were crossed, what would be 
the effect? 

A.—The locomotive brake could not be 
released with the special release valve. 

Q.—If the safety valve leaks, what will 
be the effect? 

A.—This may prevent an automatic ap¬ 
plication of the brake; but if the brake 
does apply and the triple piston and 
graduating valve in the control valve 
move back to lap position, the brake will 
remain applied, as now the safety valve 
is cut off. 


88 Helpful Hints on 

Locomotive Brake Creeps On 

Q.—If the locomotive brake creeps on 
with the automatic brake valve in run¬ 
ning position, where would you look for 
the trouble? 

A.—This is caused by a variation of 
brake pipe pressure due either to a non- 
sensitive feed valve or an overcharged 
brake pipe, which causes the triple piston 
and its slide valve in the control valve to 
move to application position, making an 
automatic application of the brake. 

Q.—If the locomotive brake creeps on, 
how should it be released? 

A.—By moving the automatic brake 
valve handle to release position and re¬ 
turning it immediately to running posi¬ 
tion. 

Q.—Why not make the release with the 
special release valve? 

A.—Where the brake is released with 
the special release valve, the triple piston 
and its slide valve are not moved to re¬ 
lease position; therefore, the brake would 
immediately reapply. 


















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